The present invention is directed to control devices for bicycle transmissions and, more particularly, to a motor control device for controlling a motor used to shift the bicycle transmission.
Bicycles, particularly recreational bicycles referred to as city cruisers, are inexpensive and are easy to ride. Consequently, such bicycles are widely used to commute to work or school. This type of recreational bicycle is sometimes equipped with an internal gear shifter to ride at high speeds over flat terrain or to ride uphill with minimal exertion. Such internal gear shifters commonly use planet gear mechanisms which are compactly housed in the wheel hub.
Because of the usefulness of these bicycles, they are sometimes taken from bike stands or the like in front of train stations and other places. To prevent this type of theft, bicycle locks such as box-shaped locks and horseshoe-shaped locks may be attached to the front or back fork to lock the wheel. However, the simple structure of bicycle locks makes them easy to unlock and remove. Thus, two bicycle locks are sometimes attached to the front and back forks for added protection. For example, a box-shaped lock may be attached to the front fork, and a horseshoe-shaped lock or chain lock may be attached to the back fork. As a result, there is less of a probability of theft because it is more trouble for a potential thief to unlock and take off two locks than just one. However, when two bicycle locks are used, it is a nuisance to lock and unlock them, particularly when a rider is in a hurry. Furthermore, even when two locks are used, bicycles can still be pedaled away and stolen by unlocking or removing the locks.
One idea for preventing the bicycle from being taken is to mount an antitheft device inside of the internal hub transmission to restrict movement of the bicycle when the transmission is set to an antitheft position. If the various operating positions of the bicycle transmission are electrically switched by remote operation from the handlebar, then only a simple operation is required for preventing theft. Such operation is further facilitated if the operating positions are controlled by a motor driven by a microprocessor running appropriate software. If, however, the microprocessor should malfunction due to static electricity, noise, or other such disturbance during running while the operating position is being switched, then there is the danger that the operating position will be erroneously switched from a gear shift position to the antitheft position, and movement of the bicycle will be restricted.